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A200554 Number of -n..n arrays x(0..3) of 4 elements with zero sum and nonzero second differences 1
14, 76, 200, 446, 836, 1368, 2134, 3140, 4368, 5942, 7852, 10064, 12734, 15836, 19320, 23374, 27956, 33000, 38726, 45076, 51968, 59654, 68060, 77088, 87022, 97772, 109224, 121694, 135076, 149240, 164534, 180836, 198000, 216406, 235916, 256368 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A200553

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 2*a(n-1) -a(n-2) +2*a(n-3) -4*a(n-4) +2*a(n-5) -a(n-6) +2*a(n-7) -a(n-8)

EXAMPLE

Some solutions for n=3

.-2....2....2...-1....2...-3...-2...-2....1...-3....0...-1....1....2...-2....2

..1...-3...-2....0...-1....3...-1....1....0....3...-1...-1...-2...-2...-1....1

..2....1....0...-1....0....2....3...-2....1...-1....2....1....0...-3....2...-3

.-1....0....0....2...-1...-2....0....3...-2....1...-1....1....1....3....1....0

CROSSREFS

Sequence in context: A093567 A296996 A270704 * A152100 A173962 A200547

Adjacent sequences:  A200551 A200552 A200553 * A200555 A200556 A200557

KEYWORD

nonn

AUTHOR

R. H. Hardin Nov 19 2011

STATUS

approved

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Last modified February 24 21:22 EST 2018. Contains 299628 sequences. (Running on oeis4.)